I'm also of this opinion. It's time; the flat Frontlines damage reductions need to be dialed back. It stunk of a lazy kneejerk reaction to melees and tanks getting overwhelmed from the sheer amount of LBs flying around when they implemented it. Not so differently from when their solution to WHMs and SMNs stacking and spamming their LBs is to just outright nerf their entire damage output in Frontlines rather than singling out what the actual problem is with those jobs.

As I said back then, I'll say now: melees and tanks are playing some Dynasty Warriors-lite with the insane amount of survivability they have in Frontlines because of the 60% damage reduction. Because of it, direct skirmishes are easily decided by whoever has the largest presence of melee and tanks by dint of every single one of them being some sort of stonewall. Nevermind tanks, attempting to kill any melee DPS with any less than 4 decent players (meaning on average you'll probably need more) is an exercise in futility without the assistance of moderate to high Battle High teammates or a NIN's LB to kill them quicker.

I get that they were probably paranoid about the "meta" being all ranged DPS sniping everything before it can even get in range to function (again), but they swung so hard in the opposite direction to the point where the correct answer to every confrontation in Frontlines is to single-out healers and ranged DPS that are even marginally overextended to even the fringes of a fight instead of punishing the Leeroy Jenkins melees and tanks that will run in and soak up an insane amount of punishment and live to run back to their team and Elixir to repeat. Part of the reason DRK+DRG stacked LBs are so effective is because it is incredibly difficult to punish them due to how much focused fire they can live through.

And as OP stated, MCH's LB is a joke (and almost always a waste) to any melee unless the MCH has a large Battle High discrepancy against their target, otherwise the melee only needs to hit Recuperate maybe once during the crosshairs animation to almost completely negate whatever is coming their way. The thing I appreciate about NIN's LB in Frontlines is that they can largely circumvent this insane damage reduction nonsense and cause people to be mindful of their HP levels and even make people with BH5 have to respect the risk of falling under 50% HP.

The problem will always be that the PvP person team will almost never fine-tune anything PvP-related for Frontlines. They will be and have been general sweeping blanket buffs and nerfs without actually interacting with or addressing specific abilities because I imagine it's too much of a mess for them to give abilities different effects and potencies between Crystalline and Frontlines.

What I think is the real big problem is that people are throwing out LBs way too frequently, which is where most of the imbalance and craziness is coming from. Some jobs are way too frequent as well, WHMs shouldn't have their LBs filled just from running to the middle platform from the spawn at the start of Secure. If you ask me, all jobs shouldn't be getting off more than 2 LBs, exceptions being the less game-changing ones, maybe they can have 3. That is, the LB gauge needs to either fill much slower or it shouldn't be filling at all unless you are in combat. LBs could stand to be more tactical and nuanced rather than "let's see how many I can fire off in this one game."